In applicant's co-pending application, U.S. Ser. No. 835,752 filed Apr. 8, 1997, there is described a five-piece open container consisting of a bottom piece and of four side pieces, each side piece having a lower edge pivotally connected to the bottom piece. The bottom piece displays at each corner a vertically extending post which cooperates with a post-receiving recess on the underside of the bottom piece to lockingly engage the containers allowing them, with their side pieces in an inwardly folded position over the bottom piece, to be stacked with similarly-constructed containers.